1. Field of the Invention
This invention relates to endless belts for conveyors and, more particularly, to connectors for making thermoplastic endless belts to be driven by sprockets or pulleys.
2. Description of the Related Art
Low tension, direct drive conveyor belts are typically used in situations where hygiene and cleanliness are critically important. For example, in food processing plants such as those that process meat products for human consumption, low tension, direct drive belt conveyors are used to transport items. Sanitation is critically important and, therefore, the endless belts used in such conveyors are conventionally made of materials that can be hygienically cleaned, such as thermoplastics or stainless steel.
Known belts include those formed of interlocking links having teeth that are adapted to engage drive sprockets. One of the problems with such belts is that food particles can become lodged in the joints of the interconnecting links. Consequently, cleaning the belts can be difficult and may require removing the belt from the conveyor system for special cleaning operations.
It is also known to use flexible toothed thermoplastic belts without interlocking links where the teeth engage drive sprockets as shown in FIG. 1. An endless belt 100 in a typical installation moves around two sprockets 102 and 103. One sprocket 102 is a drive sprocket and the other 103 is typically an idler or slave sprocket. The upper span 105 of the belt will travel in the direction of arrow 107. Each sprocket 102 or 103 has a number of transverse grooves or sheaves 104 spaced around its circumference. The belt 100 has a plurality of teeth 106 equidistantly spaced from each other on the inside surface 108 of the belt. The teeth 106 engage the sheaves 104 of each sprocket.
The belt 100 has an outside surface 10 that is fairly smooth and free of discontinuities. The belt is normally formed by butt welding two ends of the belts together at a seam 112. The outside surface 110 on the upper span 105 is normally the carrying surface for transport of items. A thermoplastic belt is usually under some tension when loaded. A thermoplastic belt under tension will stretch, which may require adjustment of the tension from time to time. Also, the belt may have to be removed from the sprockets for maintenance of the system, for cleaning, or for repair. Removing the endless belt 100 of FIG. 1 is an inconvenience, normally requiring disassembly of the conveyor frame, movement of the sprockets, and possibly destruction of the belt (or at least cutting the belt to be re-seamed later).